I. Field of the Invention
The present invention relates to communications. More particularly, the present invention relates to frame identification.
II. Description of the Related Art
Communication systems that use data retransmission to correct errors are known. Typically, such communication systems transmit data in frames that include frame numbers. At a receive system, when a frame is received with an error, a negative acknowledgement (NACK) is transmitted back to a transmit system. The NACK may contain the frame number of the improperly received frame. The transmit system responds by retransmitting the frame at some later time. A frame may be retransmitted multiple times in some systems, until proper reception is achieved. The present invention is directed to performing frame identification, with particular emphasis on improving the performance of a communication system that uses retransmission techniques.
The present invention is a novel and improved method and apparatus for performing frame identification. In accordance with one embodiment of the invention, a received frame of data is processed by generating estimates of the received frame, measuring a correlation between said estimates and stored estimates of a previously improperly received frame, processing the received frame as a retransmitted frame when said correlation is greater than a first threshold, processing the received frame as a new frame when said correlation is less than a second threshold, wherein said second threshold is less than or equal to said first threshold.